After all the research we been doing I thought to have a go and do it myself to learn the how to.
I ordered the chemicals from SiverPrint, a digital scale from Argos, "borrowed" some gloves from my work and bought some watercolour paper and tape. Simple. The trickiest part was to mix the solution A to the solution B in equal parts without the proper material.
After the first experiment I learned that the exposure times need to be of about one hour to allow for a good detailed image (which means that my first try, that was of around 30 minutes, was too dark and not very detailed) although the intensity of the sun is also a variable that not always works depending on the time.
I have done a few more after with a much better result. So, here are the pics of my experiments :)
After achieving a good result I decided to use another technique to modify the colours of the print. This technique is called Tea Toning and was used to give the print a brownish colour instead of the usual blue.
I prepared a strong solution (?lol?) of about a litre of water with 8 to 10 tea bags (normal variety, cheap Tesco kind) and let the print absorve the tea for about 2 hours. Different papers absorve the tannin of the tea differently, so it's up to you to keep on checking the prints until you reach the desired tone. 
